Electric cathode glow lamp



June 5, 1934. EWEST 1,961,748

ELECTRIC CATHODE GLOW LAMP Filed Aug. 23, 1928 INVENTOR HANS EWEST ATTORNEY Patented June 5, 1934 ELECTRIC CATHODE GLOW LAMP Hans Ewest, Berlin, Germany, assignor to General Electric Company, a corporation of New York Application August 23, 1928, Serial No. 301,591 In Germany January 11, 1928 1 Claim.

The present invention relates to electric cathode glow lamps.

Heretofore cathode glow lamps with a filling of rare gas or a mixture of rare gas have been provided generally with two electrodes, arranged at a distance of some millimeters from each other, with a short discharge section and have had resistance in series. In order to increase the chiciency of such glow light lamps, it is conternplated to so provide several series connected discharge sections in the lamp container that there can occur no discharge between neighboring dis charge sections, and this results in the practical elimination of the said series resistance.

In accordance with the present invention there are likewise provided more than two electrodes and there are produced likewise two or more discharge sections. These sections are, however, connected in a novel manner in parallel and are of different length. This arrangement permits of the operation of the lamp with several voltages with the one or the other discharge section or also with several discharge sections simultaneously. As the separate discharge sections, which are of dilferent length and which are connected in parallel, do not respond uniformly to various voltages, for example, the shorter discharge sections but not the longer discharge sections operating automatically'on low voltages, the lamp is useful for voltage testing purposes and for signalling purposes.

There is shown in front View in Figure 1 an example of construction of a cathode glow light lamp made in accordance with the invention.

Figures 2 and 3 show two diagrams of c0nnection for this lamp shown in Figure 1.

Figure 4 shows a somewhat different form of construction of the new lamp in front View and Figure 5 an example of a connection diagram for the lamp shown in Figure 4..

The cathode glow light lamp has in the manner of the known ceiling lamps atube-like glass container (1, and at each end thereof there is provided stems b, b and the usual screw bases 0, 0'. Through the stem b there are carried two current inlet wires (2, e, of which the one 11 connects a spiral electrode f with the screw base and the other a pin-like electrode g with the bottom plate of the base 0. Through the other stem 2) there is carried a current inlet wire it, which produces the connection of a screw-wound electrode 2' with the bottom plate of base 0. Between the two electrodes f, 0 there exists the separation of a few millimeters usual in cathode glow light lamps whilst between the electrodes 9 and i, and between the electrodes 7, and i a much greater separation,

that is of a few centimeters exists. The discharge sections between electrodes 9 and f on the one hand and g and i on the other hand are connested in parallel.

This can be done for example as shown in Figure 2 in that the electrode 2 together with elec trode f is connected with the interposition of a switch is with a common line Z. The other supply line m is in direct connection with the other electrode g. If a current of a low voltage, for example 110 volts, is available, then switch It is so placed (see dotted position) that the discharge passes over between the closely placed electrodes 9, f. If a current of a higher voltage, say 220 volts, is available, then by connecting switch l: to wire 12 there is produced a discharge section between the electrodes 9 and i.

When applying a higher voltage there could be produced also a discharge between the electrodes 9, but there is then danger of an excessive stress and thus atomization of the cathode f. The possibility of switching over also allows, eventually without the harmful atomization and danger of blackening, the lamp bulb to produce a glow discharge each time commensurate with the voltage.

In order to shorten the construction length of the lamp and in order to reduce the distance between the third electrode 2' from the other two electrodes 1, g to a few centimeters, the lamp is advantageously filled with a pressure exceeding the usual filling of cathode glow light lamps, thus with a rare gas or a rare gas mixture, of a pressure of more than 20 min, and that advantageously with a pressure of about mm.

The third electrode 2' can with another dimension of the electrode 9 be naturally connected together with the latter to a common supply line, whereby however care must he had, that with direct current operation the negative supply line is connected to the electrode 9. Then too the line branch 11, as indicated in. Figure 2 in dotted lines, can be connected with the supply line Z, omitting the switch is. In this case there will occur with a lower voltage a glow discharge between 9 and 2', so that then with direct current operation the two cathodes y and i and with alternating current operation even all three electrodes 9, f and i are covered with glow light and radiate light.

The possibility of an automatic operation of the second discharge section g, 2' when the voltage increases can also be usefully employed for signalling purposes. Then as shown for example in Figure 3 there can be put into the branch n leading to the third electrode 2' the secondary winding 0 of a transformer and furthermore the electromagnet 13 of an acoustic signal, for example a relay circuit 1' containing a bell q. If the primary winding 8 of the transformer is put under current by the closing of the circuit t, for example when exceeding a maximum speed or when passing through a stop signal, then there is induced in the secondary winding 0 a current, whereby the branch n is temporarily impressed with an increased voltage. This then results at once in a current flow from line Z over branch n, the electrode i, g to the supply line "In and thus the formation of a glow discharge between the electrodes 2' and g. By the electrode magnet pnow put under voltage the relay circuit 1" is put into circuit and the acoustic signal, for example a bell q is put into action. The circuit t containing the primary coils need not be permanently closed, but it suflrces if the same is momentarily closed. For as soon as there occurs a discharge between i and g, the same persists even without additional voltage, as the burning voltage of glow lamps lies as is known considerably below the ignition voltage. There thus suffices the current normally fed by the lines Z, m for the maintenance of the discharge between the electrode 2' and g initiated only by the current shock that is the temporarily higher voltage. By the automatic operation of the second discharge section 9, that is the appearance of the .second glow light in the lamp bulb, eventually in common with the sounding of the bell q there is obtained an extremely effective signal production. The steadily existing glow light at the discharge section between the closely placed electrodes g, f is thus a proof for the attendant and also possible controlling service, that the signal arrangement is in order and is under voltage.

The lamp shown in Figure l differs from that of Figure 1 only in that there are pro ided four electrodes 1, g, u in the lamp container a. Again the discharge section provided between the two electrodes 7, g has only the length usual in cathode glow light lamps of a few millimeters, whilst the parallel connected other dischar e sections between the electrodes g and u and g and i are longer by a multiple thereof.

Figure 5 shows an example of connection for the three discharge sections to be connected in parallel by means of a rotary switch :11 built into the supply line Z and bridging over the three contacts v, w, a: and a regulating resistance a connected in series with th se. If there is to be produced but one discharge between the electrodes 1 and y, then the switch 1 is turned slightly to the left and is so set, that only contact 1) is connected to the line Z. By the actuation of the regulating resistance 2 the voltage is then throttled off to a great extent and brought to that degree which just suffices for the maintenance of a discharge between the electrodes f and g. If additionally there is to be produced a discharge between the electrodes g and u then the switch y is turned somewhat further to the left, so that then also contact 10 is connected to the line Z. The regulating resistance must then naturally be displaced so that the voltage supplied increases and that the required quantity for the formation of a discharge between th electrodes g and u is obtained.

By a further turning of the switch y to the left there can then at the same time be brought into connection with the line Z the contact r. The voltage supplied must then be increased so far by further displacement of the regulating resistance 2, that there can also occur a discharge between the electrodes 9 and i. If the lamp is operated by direct current, then there are simultaneously formed on all three parallel connected cathodes 3, u, i glow light layers. If the lamp is operated by alternating current, then there naturally glows additionally the fourth electrode 9.

If the rotary switch y is provided with simple button contacts arranged at certain intervals, then when operating the rotary switch y the discharge sections between the electrodes g, f, g, u and g, i can, as may be chosen, be separately connected up. It is merely necessary in this case to have a corresponding displacement of the regulating resistance a.

The three discharge sections of this lamp as of Figure 4 can similarly as shown in Figure 3 be also automatically connected up in series, if corresponding auxiliary circuits are provided, by

the closure of which there is then impressed upon the conductors leading to the electrodes u and i a voltage sufficient for the ignition of the corresponding discharge section. There can then, as well when running over a preliminary signal as also a main signal, be brought to automatically light up each time another electrode of the lamp.

The number of electrodes and parallelly connected discharge sections, as also the shape of the electrodes and the enclosing gas container may beany chosen one according to the purpose of use.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

An electric discharge device of the negative glow type comprising a container, a plurality of main discharge supporting electrodes sealed therein and disposed linearly along the central axis of the container and a gaseous filling therein, the main discharge paths between said electrodes being of different lengths, resistance, and striking voltage, and adapted to be operated simultaneously in series.

HANS EWEST. 

